Research On Pipeline Leak Detect System Based On Dual Pressure Sensor

Leak detect system is of great importance to pipeline transportation in modern times.Pressure fluctuation is also caused by adjusting pump and valve,and this leads to false warnings in the leak detect system.So,the important measure to leak detect system is reducing false alarm rate.Pattern recognition is a common use in the leak detect system.But it can't absolutely distinguish external disturbance from the leak signal influenced by low sampling rate and interference noise.To overcome the problem,dual sensor system is proposed.The dual sensor system recognizes the false leak signal by judging the direction of signal propagation.In order to improve the accuracy of leak detect system,signal fluctuation and direction judgment method are proposed.Combination of variance and mean is used to identify the pressure signal drop.if it is sure that the pressure signal dropped,the system starts to judge the direction of signal propagation.One method is based on cross-correlation and Hilbert transform.Although this method can obtain correct result,the algorithm is very complicate.Another method is based on difference between the two signals captured by two pressure sensors.The positive or negative result shows the direction.In order to satisfy the need of dual sensor system,the remote terminal unit(RTU)is designed.RTU hardware design concludes power circuit,network circuit,AD sample circuit and so on.RTU is based on ARM microprocessor and use embedded operating system.It play the part of signals capture,signal processing,signal saving and signal transport.As the time accuracy is important,time synchronize is done in the RTU.Data transmission is based on TCP protocol,which ensures the integrity of data transmission.Central station monitoring software uses LABVIEW as the development environment.In the laboratory,the experimental platform of liquid pipeline is set up,and the data is captured by multi group experiments.The algorithm of signal fluctuation and signal direction decision in this paper is verified.The leak detect system based on dual pressure sensors can recognize the false leak signals,such as caused by adjusting pump or valve.It reduces the false warning rate greatly,and makes the system more effective.